The present invention relates to a signal processing device, a signal processing method, and a program.
A method of analyzing the periodicity of an onset time by observing the peak portion and the level of auto-correlation function of an onset start time of an audio signal, and detecting the tempo or the number of crotchet for one minute from the result of analysis is known as a method of detecting the tempo of the audio signal of musical composition and the like. For instance, in a music analyzing technique as described in Japanese Patent Application Laid-Open No. 2005-274708, the level signal in which the time change (hereinafter referred to as “power envelope”) of a short time average of the power (signal level) of the audio signal is processed is subjected to Fourier analysis to obtain a power spectrum, the peak of the power spectrum is obtained to detect the tempo, and furthermore, the tempo is corrected to 2N times using a feature quantity obtained from the power spectrum as a post-process.